The exemplary embodiments described herein relate to wellbore fluids comprising hydrated inorganic oxide materials capable of elongating from a planar shape to a fiber shape and wellbore operations associated therewith.
Wellbore fluids used in oil and gas exploration and production use a variety of additives to achieve a desired property for the fluid or to produce a desired result in the wellbore. One example of an additive that can serve many purposes is a swellable material. For example, in a swollen form, these materials can increase the viscosity of a wellbore fluid, which may allow for the suspension of higher concentrations of particles in the fluid. In another example, these materials may be placed in a permeable portion of the formation and swollen to plug or reduce fluid flow through that portion of the formation.
Many known materials are water-swellable. For example, water-swellable polymers are disclosed in U.S. Pat. No. 6,889,766, filed Feb. 27, 2003, issued May 10, 2005, entitled, “Methods For Passing A Swelling Agent Into A Reservoir To Block Undesirable Flow Paths During Oil Production,” which is incorporated by reference in its entirety. Such water-swellable polymers possess the capacity to form gel masses that resist unwanted fluid flow through the formation. The resultant gel masses readily penetrate into fractures of a subterranean formation so long as they are appropriately sized. The size of the resultant gel masses depends on the particle size of the dry polymeric material prior to hydration. These properties allow the gelled polymer particles to be packed into the formation voids, forming a seal within the formation. The disclosed swelling agents may be selected from the group consisting of polyacrylamide, polyacrylate, hydrolyzed polyacrylonitrile, carboxylalkyl cellulose, carboxymethyl starch, salts of carboxymethyl cellulose, carboxyalkyl polysaccharide, and combinations thereof.
Similarly, U.S. Pat. No. 7,287,586 filed Feb. 1, 2005, issued Oct. 30, 2007, and entitled “Compositions and Methods for Plugging and Sealing a Subterranean Formation,” discloses a composition for treating a subterranean formation, the composition comprising a water-swellable agent and a sealing agent. Preferably, the disclosed water-swellable agent absorbs greater than 100 weight % of water; and swells to greater than 100 weight % as it absorbs water. Preferably the sealing agent is greater than 0.01 weight % soluble in water; and forms a three dimensional gel structure in water. The disclosed swelling agents may be selected from the group consisting of crosslinked polyacrylamide, a crosslinked polyacrylate, a copolymer of acrylamide and acrylate monomers, a starch backbone grafted with acrylonitrile and acrylate, a polymer of two or more of allylsulfonate, 2-acrylamido-2-methyl-1-propane-sulfonic acid, 3-allyloxy-2-hydroxy-1-propane-sulfonic acid, acrylamide, and an acrylic acid monomer, and combinations thereof.
Other common swellable materials include minerals such as clay (e.g. bentonite). These known swellable materials generally swell in all directions and on the order of an about 5 to about 20 times increase in volume. However, swellable materials with different physical swelling properties (such as confining the majority of swelling to only one direction) may be useful in a variety of wellbore applications.